A biological trickling filter (BTF) was used as the major process of the upgrading and reconstruction project of a pharmaceutical wastewater station to improve the treatment effect of sulfur-containing waste gas. The pollutant removal effect and the influence of pH were analyzed. The results show that the removal of main pollutants decreases with the increases of pH of the circulating liquid. At pH of 1.7, the average removal rates of H2S, methyl mercaptan, and dimethyl sulfide by BTF are 99.62%, 85.09%, and 85.52%, respectively, and the regarding average removal loads are 26.90, 6.81, and 5.03 g/(m3·h), respectively.